DENVER - Thieves have been stealing the 420 mile marker sign so often, the state's transportation department has changed it to "419.99" in an effort to try and stop the problem.

A photo of the 419.99 mile marker sign, which is about 148 miles on Interstate 70 east of Denver, began circulating on twitter through the @JournalistsLike twitter account on Friday.

"So this is our way to test it out. So far it's working," said Amy Ford, a spokesperson with the Colorado Department of Transportation. "It's a traffic safety thing. It's a helpful thing to have these sings on the road. But people kept ripping them off."

The number 420 is often used as a reference to smoking marijuana.

The 419.99 sign has been put up within the last year Ford said.

Ford also says they've had problems with thieves stealing the 69 mile marker sign in the past.